Technical features of main reduction gear of rolling mill (1)
The most commonly used main reducer of rolling mill is the first or second grade cylindrical gear reducer. Speed ratio 7-8 is generally used as the dividing line of the first or second reduction gear. The center distance of the main gear box of the rolling mill is 1000-2400mm for the first-stage reducer and 2000-4200mm for the second-stage reducer. In the two-stage reducer, in order to make the load of the first-stage or second-stage uniform, the distribution principle of the center distance of the two stages is mainly to make the contact stress of the transmission tooth surfaces of the two stages approximately equal, and due consideration should be given to the reduction function having a small external size and weight. According to the above distribution principle, the ratio of the center distance between level 2 and level 1 is about 1.3-1.5. The smaller the ratio is, the smaller the secondary center distance is, and the smaller the profile size and weight of the reducer can be reduced if the contact stress of the tooth surface is allowed. When choosing the center distance of reducer of rolling mill, we should refer to the professional standard about the center distance.
As a gear reducer manufacturer, the gear of steel gear reducer is generally made of herringbone gear. As with the gear wheel, when the gear precision is above 8-8-7-dc, the hob retract slot should be left. In some two-stage reducers, in order to make the low-speed shaft gear and bearing load evenly, the first-stage transmission gear is usually composed of a pair of helical gears.
Check roll strength